I would like to ask you that I have found out that many food companies and clothes shops support the Jews eg. Marks and Spencer, Nestle, Nescafe. Should I stop buying from these shops and stop eating companies that support the Jews?
Boycotting Jewish products is not something which is imperative for the Muslims. It is purely a matter of strategy. If Muslims think that for some reason they have to boycott Jewish product they can take such a decision.
Also, this stance can only be affective as well as morally justified if Muslims stand on strong moral grounds and are themselves not guilty of misconduct and excesses against the Jews. If they stand on strong moral grounds, they will find the backing of the world community with them. They must do some serious soul searching if they want to go this far.
Moreover, this decision will only carry weight if it is taken at the level of the whole Ummah or at least a major portion of it. Individual decisions in this regard may be very inconsequential.